Controlling system



June 24 1924. I 1,498,530 w. P. ALBERT CONTROLLING SYSTEM Filed Mag 11. 1192:

mmwm/ Patented June 24, 1924i.

WALTER 1. ALBERT, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO WESTERN ELEC- TRIO COMPANY, INCORPORATED, OF NEW YORK, N. Y., AGORPORATION OF NEW YORK.

Application fil ed May 11,

to impulses generated by some form of im-- pulse sending mechanism.

Step-by-step mechanisms are wellknown' in the automatic telephone art, where they may be used either as switches to establish telephonic connections, as registers, as number indicatmg 'dev1ces, or for performmg a variety of functions as progression controlling apparatus and means for associating various pieces of apparatus with one an other. In order to meet the requirements of the modern automatic telephone system, step-bystep devices which are operated under the control of impulse sending devices, must be capable of a high speed of operation. This means that the impulses generated in the controlling line succeed one an-- other at a rapid rate. If theline is of considerable length it will have varying characteristics as regards its impedance a'nd'leakage. As a result, lines of various lengths will differ in their transmitting qualities, so that it becomes difficult to cause a fixed form of mechanism to respond uniformly under various conditions of line length. Local and temporary disturbances in proximity to the controlling line may also affect the transmission qualities of the line. A dial which has become imperfect due to wear or poor adjustment of the governor may also produce impulses of undesirable characteristics.

It is usual in systems in which step-bystep devices are controlled, to provide a relay which follows the pulses produced "by I the impulse generating device.

If the various indu'ctive'and capacity effects are of suflicient strength it'rmay happen that the pulses actually received by this relay are considerably distorted or mutilated, even though theyare generated at a uniform rate. Thus, it'would e possible that due to the CONTROLLING SYSTEM.

1921. Serial No. 468,478.

characteristics of the line, the impulse retime.

Previous circuits have been devised, as for example, those shown in my copending application, Serial No. 878,100, filed May 1, 1920, Patent No. 1,499,573, March 27, 1923, in which the evil effects of distorted impulses may be overcome. My invention however, contemplates an improvement over such systems, in thatit also overcomes'to a marked degree the evil effect of line leakage in addition to insuring correct operation upon the receipt of mutilated pulses.

It is obvious that if sufficient line leakage is present the impulse receiving relay 'will have a tendency to remain energized after the contact break at the dial if the leakage occurs between the relay and the/impulse sender, since this leakage tends to shortcircuit the contacts of the sender.

It is the object of this invention to provide circuits for controlling the operation of the stepby-step mechanism, such that the switch will respond to mutilated impulses even on a line of considerable leakage without danger of losing synchronism with the sending device.

A feature of the invention is the use of a doublewound impulse receiving relay, the

two windings of which are provided with It is thought that the invention win best be understood from the following detailed description, reference being had to the accompanying drawing.

The drawing showssuch portions of a controlling circuit and'a step-by-step device controlled by an impulse sender as are necessary to an understanding of the invention V For the sake of simplifying the description, it has been assumed that the step-by step device, indicated generally at 12, is a register switch to be positioned under the control. of a subscribers substation sende indicated at 3. The operating portions of the register switch include a stepping mag net 8, 'a stepping pawl 9, a ratchet wheel 10, and a holding pawl 11. The operation of the system is as follows.

When the calling subscriber removes his receiver from the switchhook (not shown) the line circuit is completed and line relay 2 is ener ized over a circuit extending from groundec battery, resistance 1, right-hand winding of relay 2, through the switchhook contacts, impulse springs 13 and 14, thence over the other side of the line and through the right-hand winding of resistance coil & to ground. Relay 2 is energized in this circuit and completes a circuit from grounded battery, winding of slow-release relay 5, resistance 6, armature and front contact of relay 2 to ground. Relay 2 upon energization also completes a circuit through its left hand winding from grounded battery, resistance 1, left-hand winding of relay 2, resistance 6, armature and front contact of relay 2 to ground. The direction of current flow in this circuit is such as to cause the left-hand winding of relay 2 to magnetically oppose the right-hand winding of such relay, thus making the relay very quick to fall off when dial springs 13 and 14 are opened.

When the dial springs are opened to send the first impulse, line relay 2 is dcenergized and completes a circuit from grounded batter winding of stepping magnet 8, winding of slow-release relay 7, armature and front contact of slow-release relay 5, which reiains energized between impulses, and the armature and back contact of relay 2 to ground. Stepping magnet 8 and relay 7 are energized in this circuit. It should be noted that at this time the righthand operating winding of relay 2 is completely short-circuited by ground at its own armature and back contact, this circuit extending through contact springs 15 and 16, controlled by the stepping magnet 8, through the armature and front contact of'relay 5. If the sender should again complete the dial circuit before stepping magnet 8 has completed its stroke, relay 2 cannot be energized, due to the short circuit just traced. It is to be observed that during the interval in which relay 2 is deenergized a circuit is in existence from grounded battery, windlng of relay 5, lefthand winding of relay 2 and thence to ground, at the armature and back contact of relay 2, as described. Current flow in this circuit is not sufficient to cause the energization of relay 2, but is in a direction to cause the left-hand winding of this relay to magnetically aid its right-hand winding when such winding is energized by the closure of the dial springs. This makes the relay very quick to energize when the dial circuit again completed.

lVhe-n stepping magnet 8 has fully attracted its armature, contacts 15 and 16 are opened and allow line relay 2 to be energized upon the subsequent closure of the impulse circuit.

It is to be observed that if relay 2 receives a mutilated pulse of such character that the break in the impulse circuit is of very short duration, correct operation will take place nevertheless, because the right-hand operating winding of relay 2 is short-circuited until magnet 8 has caused the register to be advanced a full step.

If the impulses received by relay 2 are dis torted in a manner such that the open condition of the impulse circuit exists for a longer time than normally, no harm can be done since relay 5 is positively prevented from releasing, since it has a circuit through the left-hand winding of relay 2, until the switch has advanced a full step. This additional holding circuit should provide ample time to prevent the release of the relay.

If the opened condition of the impulse circuit continues to exist after the switch has made a full step, the circuit for relay 5 will be opened at contacts 15 and 16 and slowto-release' relay 5 will be -released after a predetermined time opening the circuits for the stepping magnet at the armature and contact of relay 5 thus allowing the stepping magnet to release.

The resistances and windings of the various relays in the circuit are so propor- I tioned that the ampere-turn value of. the left-hand winding of relay 2 is greater than. the ampere-turn alue of the leakage current in the winding. This produces a material reduction in the 'e'tlect of line leakage on pulsing. Thus when the relay 2 is energized, the opposing effect of its left-hand winding overcomes the tendency of line leakage to hinder proper release of the relay.

.lt'should also be observed that the effect of the left-hand winding, of relay 2 is of greatest benefit when needed most, that is, when the dial circuit is closed before the magnet contact opens. In this case, the magnetic condition built up in the left-hand winding makes the relay very quick to operate and open the circuit of the steppin'gnia-gnet.

VVha't is claimed is:

1. In a controlling system, a -step-'-bystep device, an operating magnet therefor, an impulse receiving relay, an operating winding for said relay, means for transmitting impulses over the circuit :for said operating winding to actuate said relay, a second winding for said relay, control circuits, means to shift said control circuits so that at certain times said second winding magnetically -opposes said operating winding to 'mak said relay quick to release, and so that at other times said second winding magnetically aids said operating winding to make said relay quick to operate, and a circuit for said operating magnet controlled by said relay.

2. In a controlling system, a relay, an operating winding for said relay, means to actuate said relay in response to impulses directed to said operating winding, and means for rendering said relay quick to operate upon the completion of "a circuit through said operating winding, said means comprising a second winding for said relay, a circuit for said second winding, and means to complete said circuit during the nonoperated condition of said relay.

3. In a controlling system, a step-by-step device, an operating magnet therefor, an impuse receiving relay, an operating winding for said relay, a second winding for said relay, and a circuit for said second winding controlled at normal contacts of said oper ating magnet and of said relay, the magnetic relation of said windings being such as to render said relay quick to operate when said second winding is energized.

4. In a controlling system, a relay, an operating winding for said relay, a second winding for said relay, circuits for said windings, means for transmitting impulses over the circuit for said operating winding to actuate said relay, and means for rendering said relay quick to energize at certain times and quick to release at other times, said means including means to complete desired ones of said circuits at desired times to produce a variable magnetic relation between said windings.

5. In a controlling system, a step-by-step device, an operating magnet therefor, an impulse receiving relay, an operating winding for said relay, a second winding for said relay, a circuit for said magnet controlled by said relay, and means to produce a variable magnetic relation between said windings to make said relay quick to operate at certain times and quick to release at other times, said means including a circuit controlled by said magnet for shunting said operating winding. 7

6. In a controlling system, a step-by-step device, an operating magnet therefor, an impulse receiving relay, an operating winding for said relay, a second winding for said relay, control circuits, and means to shift said control circuits so that at certain times said second winding magnetically opposes said operating winding and so that at other times said second winding magnetically aids said operating winding, a circuit for said magnet controlled by said relay, said means including a circuit controlled by said magnet for shunting said operating winding.

7 In a controlling system, a line, a device for transmitting impulses over said line, an impulse receiving relay to be operated under the control of said sending device, and means to insure synchronism between said sending device and said relay under varying conditions of line impedance and line leakage.

8. In a controlling system, a step-by-step device, an operating magnet therefor, an impulse receiving relay, a slow-to-release relay, a circuit for said slow-to-release relay completed under. the control of said impulse receiving relay in the energized condition of said impulse receivingrelay, and an auxiliary circuit for said slow-to-release relay controlled jointly at normal contacts of said magnet and of said impulse receiving relay.

In witness whereof. I hereunto subscribe my name this 10th day of May A. D., 1921.

"WALTER P. ALBERT. 

